This invention relates to power transmissions, and more particularly, to multispeed planetary gear power transmissions having at least one reverse torque and speed ratio and at least three forward torque and speed ratios, the lowest of which forward ratio has a planetary gear set unique thereto.
In prior art planetary gear transmissions, the gearing is compounded in such a manner that changing the low ratio gear set affects the other ratios in the transmission. In these systems, there is no planetary gear set unique to the lowest ratio. Other prior art transmissions have a single planetary gear set for the low ratio. However, in these transmissions, the overall ratio coverage is limited, and also these transmissions are not compatible with one-way drive mechanisms utilized for timing control during a ratio interchange. Thus, the shift timing controls in these transmissions is somewhat complicated.